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Avian Influenza (Bird Flu)

Avian influenza

Avian influenza, or bird flu as it’s often known, has been in the news both here and abroad recently. Following a smaller outbreak in 2020, the UK had its largest ever outbreak in poultry beginning in October 2021. As a result, it was compulsory to house birds inside for some months and this remains in force in hotspot areas. In the US, they are also experiencing what could be their worst ever outbreak of the disease, with 37 million domestic birds already culled.

There have been large numbers of fatalities within the wild bird population as well, with great skuas suffering a catastrophic breeding season in 2021. An estimated 16,000 barnacle geese died on the Solway Firth over the 2021/22 winter season.

What Is Avian Flu?

Avian flu is the name given to a disease in birds caused by a group of highly contagious bird flu viruses. These spread naturally among wild birds (often aquatic birds such as ducks, swans and geese) worldwide but also infect domestic poultry. Before the 1990s, outbreaks in domestic settings were sporadic and easy to contain. The huge increase in intensive poultry farming since then, however, has led to more frequent and difficult to manage events.

Bird flu strains are divided into two types:

  • Highly pathogenic avian influenza (HPAI). This is the more serious of the two and often fatal in birds. Onset is usually extremely rapid and usually fatal.
  • Low pathogenic avian influenza (LPAI). Less serious and infected birds may not show obvious signs of infection.

Both types are spread between birds by direct contact or through infected body fluids or droppings. In domestic birds, bird feed, water, dirty clothing, footwear and machinery can also spread it. This means that strict hygiene measures and biosecurity are extremely important for farms that keep poultry. In wild bird populations, shared bathing spots, roosting sites and scavenging behaviour can all contribute.

Avian influenza

As with many viruses, the bird flu viruses change quickly and mutate. This could lead to new strains that can spread to humans or other animals more easily. Currently, bird flu very rarely spreads to humans.

Spring 2022: The Current Situation In Wild Populations

There are signs that birds returning to their breeding grounds in the UK this spring are showing signs of infection. Large numbers of dead birds belonging to a number of species have been noted at sites across Scotland, potentially spreading as pink footed geese moved north earlier this spring. Eider colonies on the Cromarty Firth, Loch Fleet near Golspie and gannetries from Troup Head in Aberdeenshire to Noss in Shetland are among sites affected. Testing has not been carried out extensively, but when it has been, it clearly shows the disease is not as confined to aquatic birds as previously thought. This is a huge cause for concern.

Avian influenza

Distressing footage of uncoordinated and lethargic great skuas has been recorded in the last few weeks in Shetland, a breeding stronghold. There are fears that the disastrous breeding season of 2021 will be repeated. The UK holds 60% of the world’s breeding population of great skuas, or bonxies, so losses here have a massive impact on their overall status.

How To Spot Bird Flu

HPAI can produce any of the following symptoms in birds, either on their own or in combination:

  • Loss of balance and coordination
  • closed and very watery eyes
  • lethargy
  • unresponsiveness
  • swollen head
  • tremors, drooping wings or dragging legs
  • signs of breathing difficulties (such as gaping, sneezing or gurgling).

If a group of birds are found dead together, this could also be a sign that bird flu is present.

What To Do If You Find Suspected Cases

Although a wild bird may have died from a number of natural causes, if you find a sick or dead bird that you suspect has been infected by bird flu, it is essential you do not touch or pick it up.

You should report your find to a specially set up Defra helpline: 03459 335577. They will collect specimens to test and find out if flu is the cause of sickness or death. This helps them track the spread of the disease.